Hi,
we were recently asked to calculate the volume of a geological layer as part of a site investigation. when exploring different options we were confused when we found that two different methods which, we think, should produce the same volume varied quite a lot and so wondered whether a) we were wrong or b) it was a product of the way Arc performs the calculations. The first method was to interpolate two different surfaces of ground elevations at the top and bottom of the layer and use cut fill to create a volume. The second method was to generate a constant raster with a value of 0 and then use the thickness of the layer (top surface minus bottom surface) to perform the cut/fill operation.
Any suggestions/ideas are welcome.
Thanks,
Rob
